Apparatus for producing carbon dioxide snow blocks



4 sheets-gn t 1 w. E. Z IEBER Filed April 27, 1940 3mm Po z QX) LURia/mE. Zia/hep Q1 Hm 21 1g H s zru 39 APPARATUS FOR PRODUCING CARBON DIOXIDESNOW BLOCKS Aug. 26, 1941.

Aug. 26, 1941. w Z IEBER 2,253,880

APPARATUS FOR PRODUCING CARBON DIOXIDE SNOW BLOCKS Filed April 27, 19404 Sheets-Sheet 3 1) CHECK BELIEF VALVE OILFI PRESSURE.

LOW DQESS E PUM v (Ittornegs Aug. 26, 1941.

W. E. ZIEBER 4 Sheets-Sheet; 4

Filed April 27, 1940 Zhwento; E. Zie/be'v attornegs 7 5 u 1 a \w \v a 16 1 i 5 h 1 1 ,1 010 A W;

Patented Aug. 26, 1941 William E. Zieber, York, is. asslg'r'lor to YorkIce Machinery Corporation, York, Pa.,. a corporation 01' DelawareApplication April 27, 1940, S erialNo. 332,051

18 Claims.

This invention relates to a method of and apparatus for making solidcarbon dioxide and particularly carbon dioxide snow blocks.

The manufacture of carbon dioxide snow, according to methods heretoforepracticed, has never been a rapid process, because considerable time isrequired to flash the liquid into snow. If the flashing is acceleratedunduly, in an effort to shorten time, the resulting drop in temperatureis are characteristic of too rapid snowing operation.

Snow blocks produced by apparatus of the prior art are objectionable inthat the corners are soft and frequently fall away during or after theremoval of the block from the press. invention provides for productionof firm dense blocks in which the corners are strong and compact and arenot subject to prior art difliculties. Hence the product is salable andattractive, and the loss of snow resulting from soft corners isdefinitely overcome. Prior art apparatus has also The presentthe snowand press chambers, and the cooperatins p r Fig. 4 is a view similar tothat of Fig. 2 with parts in section to show the snow chamber and liquidinlet;

Fig. 5 is a diagrammatic viewof one form of hydraulic mechanism suitablefor actuating the press, the press chambers and the actuating cylindersbeing shown in section and in a single plane; 4

Fig. 6 is a partial horizontal section substantially on the line 66 ofFig. 2;

Fig. 7 is a side elevation, partly in section, of the valve operatingmechanism associated with the press chamber, the section being taken online 1-1 of Fig. 6;

Fig. 8 is a sectional view through the valve of Fig. 7, with the valvein closed position;

Figs. 9 to 14 are sectional diagrammatic views illustrating the stepsinvolved in a cycle of operation of the press.

been ineflicient in removing snow from the snow chamber by gravity or byuse of gas pressure, the first because of the time required for suchremoval and the loss in gas, the second because of jects and advantageswill appear from the de-- scription when it is read in connection withthe drawings, in which: v

Figure 1 is a front view of one form of press embodying'this invention;

Fig. 2 is a side elevation of the press shown in Fig. 1 looking fromright to left as to that figure; Fig. 3 is a view similar to Fig. 1, butwith parts broken away to show the interior construction of constructionadapted to receive'and support the.

dstructural element of the press.

Briefly stated, the press of the present invention involves the use oftwo chambers each having one end open and the chambers being insubstantial longitudinal alignment with one another, one chamber beingfixed and the other having anopenend movable toward and from the openend of the fixed chamber. Means are provided for closing off the openend of the fixed chamber, and this closing means is also adapted to forma sealing means for the open end of the movable chamber. Means areprovided, to form snow in the fixed chamber and to force that snow outof the fixed chamber into the movable chamber while the two areseparated. The movable chamber contains pressing means for the snow,transferred to it after formation in the snow chamber. The

movable chamber may be moved away from the clude a unified control sothat operation of the various components of the press may becoordinated.

Referring now to the drawings, reference character ll designates a bedor base of any suitable Supported on the base II are four verticalcolumns I! which are tied together at their upper ends by plate M. Thisplate is formed to support the fixed or snow chamber which in turncarries the motor cylinder used to actuate the plunger which displacesthe formed snow from the fixed to the movable chamber. 'The plate I4 isstiffened-by lateral wings or flanges 28 which give it the strengthnecessary to withstand the loads encountered in the operation of themachine. The plate M has a central opening |5 in which the lower end ofthe upper or stationary snow chamber I6 is seated. Mounted within thechamber l6 and movable up and down therein is a ram or piston controlledby a piston rod-l8 and adapted to be actuated by fluid pressure suppliedabove or below a piston |9 working within a cylinder 2|. As shown in thedrawings, the inlet and discharge connections for pressure fluid to andfrom opposite ends of the cylinder 2| are designated 22 and 23. v

As here shown, the upper end of chamber I6 is closed by a head 24, thepiston rod |8 passing through a stufling box 25 mounted in the head. Aspacer member 26 is bolted to the upper face of head 24 and carries a.head 21 bolted thereto and provided with a stufling box 28 for thepiston rod IS. The upper end of cylinder 2| is closed by a head 29. Itwill thus be seen that when pressure fluid is supplied to the pipe 22,the piston I9 is lifted and lifts with it the plunger l1. If, however,pressure fluid is supplied to the cylinder 2| through pipe 23, piston l9moves downwardly carrying with it the piston rod I8 and the plunger I!thus ejecting snow which as explained is formed in the chamber I6.

The snow chamber I6 is provided with means best shown in Figs. 2 and 4for introducing subcooled liquid carbon dioxide under pressure into thatchamber, and flashing it into snow. As shown, one wall of the chamber l6contains a constricted inlet opening 3| of tapered nozzle formationhaving an inlet connection controlled by a valve 33. Thevalve chamber 34is formed within a body 35, and has a transverse area substantiallygreater than the transverse area of the discharge end of inlet nozzle3|. Connected to valve 33 is a valve stem 36 which passes through astufiing box 32, the rod serving to move the stem longitudinally whenshifted by lever 31 pivoted at 38 to a bracket 39 and connected to acollar 4| on the valve stem. 36. A cap 30 carries the stuffing box 32and has an elongated valve stem guide 48 within chamber 34. The end ofthe valve stem 36 extending beyond lever 31 has rigidly secured to it alever 42. The valve 33 seats when it is moved to the extreme righthandposition of Fig. 4 as shown. Movement of the lever 31 to the left inthat figure carries the valve away from its seat to permit liquid carbondioxide to flow through the inlet 3|. If the low temperature of theliquid carbon dioxide should cause the valve 33 to freeze to its seat orif frozen particles should hold it far enough away from its seat toprevent sealing, the lever 42 may be swung to rotate and thus free thevalve or ensure its sealing. It will be observed that the liquid inletchamber 34 is of much greater cross section than the inlet 3| and thisdifference in cross section is relied upon to keep the liquid undersuflicient pressure to prevent the formation of snow until the liquidissues from the end of the nozzle.

In addition to the liquid inlet 3|, the snow chamber |6 has a flash gasofitake 43 equipped with a manual stop valve 44 which is wide open whenthe machine is operating. This offtake in the preferred arrangement isconnected to the inlet of the first stage compressor in order to avoidloss of flash gas.

The ofitake 43 is so dimensioned as to exercise a moderate throttlingeffect on the off-flowing gases. This does not establish any definitepressure in the snow chamber, but it does limit the rate of snowformation to an extent that will prevent the formation of ice ascontradistinguished 'from snow, and it does limit the entrainment ofsnow particles in the oft-flowing flash gas. During the introduction ofliquid, the valve 43 is wide open and does not perform any regulatoryfunction.,; Such reg lation as is, had, is effected by the fixedsizeg'of the nozzle orifice 3| and the fixed size of the flash gasofitake. connection. This relieves the operator of any manipulativecontrol whatsoever, and does away with all pressure regulating valves orother automatic appliances. The only control which the operatorexercises is to vary the duration 'of openingof the valve 33, accordingto the size of the block that he desires to form. Development ofpressure within the snow chamber is,-

however, limited by a safety valve 45, which may be set to relieve thepressure at any definite value, preferably in the neighborhood of 100lbs. gauge pressure. This pressure is above that normally developed inthe snow chamber so that the valve 45 is merely a safety device.The'chamber |6 may also be provided with a pressure gauge 46 so that thepress operator can ascertain what the operating pressures within thesnow chamber are. The chamber l6 and the hydraulic actuating cylinder 2|which operate the transfer plunger IT, can be, and preferably are,constructed comparatively lightly as they have no snow pressing action,and hence are never heavily stressed.

The base II, as best shown in Figs. 2 and is formed to receive andsupport a pair of hydraulic cylinders 41 and 48, arranged as shown, eachhaving a piston for operating piston rods 49 and 5| rigidly attached tolugs 52 on the vertically movable press chamber 53. 53 is closed at itslower end by a head 54. Through this head passes a rod 56, sealed by apacking gland 55 and secured to a press plunger 51 within the chamber53. The cylinders 41 and 48 may be supplied with hydraulic pressurefluid to raise and lower the press chamber .53, through connections 58and 68, respectively. and the construction is such that these cylindersand the piston rods moving therein serve as guides and supports for thepress chamber.

The rod 56 is connected at its lower end to a yoke 58. Two piston rods59 and 6| attached to yoke 58 pass through stufllng boxes 62 in thelower heads of hydraulic cylinders 63 and 64. Piston rod 59 carries atits upper end a piston 65, and piston rod 6| carries a similar piston66. The cylinders 63 and 64 are mounted in plate l4 and are seated inopenings therein. The upper ends of the cylinders 63 and 64 are closedby heads 61, each containing hydraulic connections 68. There are alsohydraulic connections 69 at the opposite ends of these cylinders. Itwill be seen that when hydraulic pressure fluid is supplied through theconnections 68, the pistons 65 and 66 will be lowered and will actthrough yoke 58 to lower the plunger 51. In similar manner, admission ofhydraulic pressure fluid through connections 69 will elevate the pistons65 and 66 and hence the plunger 51.

From the foregoing description it will be seen that mechanism isprovided for forming carbon dioxide snow in the chamber I6 and also formoving plunger |1 up and down in that chamber to eject the snow. Thehydraulic cylinders 41 and 48 are operative to raise and lower the presschamber 53 into and out of contact with the head M in alignment with thesnow chamber l6.

The press chamber raise and lower the adapted to seal the open end at IIto the base I I of the press.

Hydraulic cylinders 88 and 84 are effective to plunger 51 in the presschamber 58. It is essentialthat means be provided for closing the openend of snow chamber I8 during the snowing operation. Such a means isillustrated in Figs. 3 and 4 of the drawings.

Referring to Fig. 4 of the drawings, reference character II designates aclosure plate adapted to be moved into and out of sealing engagementwith the lower end of snow chamber I6 and also of press chamber 53 inthe pressing operation, at which time the parts occupy the positionsshown inFigs. 3 and 4. The closure plate II has 9. depending boss orprojection I2 adapted to flt into the press chamber and assist theconsolidation of the snow which is transferred into that chamber fromthe snow chamber above. This has the effect of compacting the corners ofthe block as will be explained.

A vent port 98 in boss or projection I2 is connected by aflexible hose99 with offtake 43 and serves to vent gas from the press chamber duringa pressing operation. In this way the gas escaping from the block whileit is being pressed is recovered along with the flash gas from the snowchamber. The plate II may be swung ,rearwardly from the position shownin Fig. 3 (toward the right in Fig. 4) out of sealing engagement withthe snow and press chambers when press chamber 53 is lowered far enoughto clear the projection 12. swinging function, the plate 1I carries oneach lateral side a pair of spaced pins 13 connected by rods 14 to'abifurcated member 151 The members I straddle and are plvotally connectedtothe middles of levers 18 pivoted at one end The other ends of levers16 have connected to them at 18 tie- 'rods I8 terminating at their upperends in eccentric straps 8I. Movable within the straps BI and attachedto an operating lever 82 are eccentrics 83. The pivot 'I'I for the barsI8 is mounted in two spaced brackets 84 so that movement of the lever 82permits a limited upward locking movement of the pressure plate II withreference to snow chamber I6. Upward movement of press chamber 53 andsealing engagement between the upper end of this chamber and the lowerface of plate 'II is accomplished through the hydraulic cylinders '41and 48.

The closure plate II carries a handle 85 which press is such as to avoidall freezing up of the parts andinsures continuous operation of thepress.

Inaddition to it is convenient and frequently necessary to have meansfor'indic'ating the position of the'press plunger 51 within the presschamber 58. As here illustrated, a column l2 (Fig. l) carries grad-'uations 88 with which a rod 89 attachedto. the yoke 58 cooperates. Asuitable guide, such as 9|, may be carried by the column toguide the rod89 in its up and down movement. The graduations at 88 may be of anydesired character to For performing this all three have the operator maygrasp to shift the plate when it is desired to move the closure plate toor from sealing position. Rearward movement of the closure plate islimited by engagement between the plate and a U-shaped bracket 86 havingits ends attached to two of the columns I2. The closure plate may bemoved forwardly to sealing position by a foot treadle 81 attached to oneof the bifurcated members I5, and it may be locked against the chamberI6 through lever 82.

Since the closure plate II is pivoted on the base of the press by rodsI4 and member 18, its mounting is thermally isolated from both the snowand the press chambers and the only heat transfer that can occurbetweenthe plate and these chambers is that occasioned by direct contactbetween the plate and the chambers during the pressing and snowingoperations. Thus, while snow being formed in the snow chamber isshowered on one face of the plate and pressed in the press chamber indirect contact with the other face of the plate, the thermal isolationof the plate from the heavy metal masses of the of the cylinderscharacter.

. they admit pressure selectively to one end while in which both trivedthat in its connections 58 and lift the press chamber.

indicate the depth of the block being pressed or its weight.

Although various types of mechanism may be shows in diagram the threesets of piston motors.

used in the press, the three control valve units for the motors, and themeans for developing the hydraulic pressure controlled by the controlvalve units and used tooperate the press motors.

There are three control valve units, namely valve unit I8I, withactuating lever I82, valve unit I83 with actuating lever I84, and valveunit I85 with actuating lever I88. All three valves are hollow and .ofthe balanced piston type and three similar positions, down indicated bythe letter D, upf indicated by the letter U (which are the extremepositions of the valve), and neutral or mid-position indicated by theletter N which is a lap position cylinder ports are closed so that ahydraulic lock of the controlled piston is afforded. The construction ofthe valve units is shown indiagram in Fig. 5. The valve proper as shownin each case is simply a hollow spool valve of the inside supply endexhaust type but may be any hydraulic piston type valve suitably ported.All three valve bodies are connected to the high pressure supplymanifold I8'I and to the exhaust manifold I88 as shown. The exhaustconnection of the valve unit I8I leads upward so as to trap liquid inthe valve, for a purpose to be explained. 1

The piston valve of valveunit IN is so conneutral position it blanks the88 to the two ends of the motor cylinders 41 and 48. Inthe up. positionit connects the lower connection 58 to supply and the upper connection88 to exhaust, while in the down position it connects both the upper andlower end connections 58 and '68 to exhaust.

The rising exhaust connection prevents. the oilfrom draining away fromthe valve body, so that as the press chamber lowers by gravity both endsremain oil-filled. Thus valve unit I8I in its neutral position can lockthe press chamber. In its up position it adinits pressure fluid belowpistons in cylinders 4'l; 4-8 to In its down position it merely permitsthe press chamber to descend b, gravity, by blanking supply andconnecting the opposite ends of cylinders 41, 48 together.

' i'he valves I83 and I85 are of slightly different They have a neutrallap position and connecting the other end of the cylinder to exhaust.The result is that the press plunger and the ejector plunger are eachcapable of hydraulic the mechanism just described,-

the main flow paths alone power operation in both directions. Thus thevalves I and I are simply a positive lap reverse valve gear of thebalanced piston type with inside supply and end exhaust.

The valve I05 is shown in its "up position to which it is biased by aspring as shown. The connection 22 of the cylinder 2I leads directly tothe body of valve I05, but-a special double connection is interposedbetween the upper connection 20 and the body of the valve I05 for thepurpose of assuring that the press chamber 03 will be in its lowerposition at the time the snow is ejected from the snowing chamber I0.Thus between the connection 23 to the top of cylinder 2| and theconnection 230. to the valve I05 there are two parallel paths. The firstof these is through check valve 231) which permits flow from 20 toward230 but closes against reverse flow. The second connection is through avalve mechanism indicated generally by the numeral 20c applied to itsvalve body. This valve mechanism is shown in detail in Figs. 7 and 8.

As shown in these figures, a balanced piston valve I0! is urged by aspring III in an outward direction to a position in which it interruptscommunication' between 23 and 23a. The end of the valve I00 protrudesand carries a roller I I2 which is in the path of a cam II3 moving withthe press chamber 50. The actual construction and location of the cam H3is indicated in Fig. 7 and a diagrammatic showing is adopted in Fig. 5.

In Fig. 7 the valve body 230 is shown carried on a bracket II4 bolted tothe member I2, while the cam H3 is bolted to yoke 52. Assume now thatcontroller I05 is in the up" position and it is desired to move thepiston I0 and the ejector I'I downward. Controller I00 is moved to the"down" position which connects 2311 with the supply and 22 with exhaust.The supply flow cannot pass the check valve 23b and hence must passthrough the valve 22c which will be open only if the press chamber is inits lowermost position. In such position the cam II3 pushes the valveI00 inward to connect 2011 with 23. In this.

way a hydraulic interlock is provided which assures that the transfer ofsnow from the snowing chamber to the press chamber will occur when thepress chamber is in its lowermost position.

The pressure developing mechanism is also shown-in Fig. 5. H5 representsa tank or sump containing the hydraulic fluid, ordinarily oil. Thereturn line I00 discharges freely into the tank Iii. A motor II6 drivestwo pumpsIIl and III. The pump III may be of the rotary type and is oflarge discharge capacity, but capable of discharging against apredetermined pressimply admits the pressure in the high pressure lineI01 to react against the motor or pressure responsive element of therelief valve I24.

This relief valve is so adjusted that when pressure in pipe I07 exceedsthe predetermined pressure (assumed above to be 400 lbs.) the valve I24opens and unloads the pump I". At such times the check valve I23prevents back flow from line I01. The unloading flow is by way of thedischarge connection I20.

The high pressure pump III has a partial unloader I21 which is subjectto control by pressure in control line I20 and may be of the socalledleak stroke type. The control line I20 is connected with the connection00, which is the connection to the upper end of the press cylinders 03and 64.

When the press plunger 51 is lowered, there is oil pressure inconnection "J The partial unloader is so contrived that under theseconditions the high pressure pump IIO develops a discharge pressure ofsay, 750 to 1,000 lbs. When, however, the press cylinders 03 and 04 areactive for pressing operation and the connection 60 to the upper end ofthe press cylinder is exhausting, the partial unloader is inactive andthe pump III develops its full discharge pressure, say 2,000 lbs. anddelivers it to connection 00.

It will be obvious from the above that during ordinary movements of thehydraulic pistons and until a resistance equal to the predeterminedpressure in the hydraulic cylinders is encountered, the large capacitypump I I1 furnishes pres. sure fluid. From this it follows that themotion of the plunger; will be rapid so long as they encounter noserious resistance. When the back pressure in any hydraulic cylinderbuilds up to the predetermined pressure, the large capacity pump IIIceases to deliver because it is unloaded by the relief valve. I

At such times the small capacity high pressure pump takes over anddevelops the necessary opsure, say 400 lbs. per square inch, whereas thepump III is of the positive displacement type having a relatively smalldischarge capacity but capable of discharging against a relatively highback pressure, say 2,000 lbs. per square inch. The pump III has asuction connection H9 and the pump IIO has a suction connection I2Ithrough which the pumps draw oil from the sump H5.

The pump III discharges through connection I22 and a check valve I2'3 tothe high pressure supply line I01. The pump IIO discharges directlyintothe supply line I01. In the connec-' tion I22 and hence between thepump I I1 and the check valve I2! 'is a relief valve I24 which respondsto. pressure in the high pressure line I01. To enable the relief valveI24 to respond directly to pressure beyond the valve I23, a pressuretransmitting connection I20 is used. This inch. Inthis crating pressure.If the plunger 51 is not in operation in an upward direction, themaximum pressure is limited by the partial unloader mechanism I 21, butif the press plunger 01 is in action the available pressure is 2,000lbs. per square way, rapid motion until load is encountered is provided.Reasonable pressures are provided for the ejection and transferoperations and for the raising and lowering of the press chamber 03,while a much higher pressure is available for the pressing operationdeveloped by the upward motion of the plunger 51 alone or in conjunctionwith themes chamber 53.

The reasonfor using the cam Ill and valve 230 is to prevent the operatorfrom performing the useless maneuver of raising the press chamber 03 toreceive the charge. The ,charge is simply pushed out of the snow chamberand falls into the press chamber while the press chamber is in itslowermost position. Time is saved by compelling the operator to make thetransfer under the conditions stated.

Referring now to Figs. 9 to 14, inclusive, the cycle of operation of thepress v. 11 be described.

Fig. 9.Closure plate II is sealing the lower end of the chamber I0, inwhich snowing is proceeding. The press chamber 53 and the press plunger01 are in their lower positions ready to receive a charge. At the tion,the closure II is swung to one "side and valve handle I00 is movedmomentarily to down position. Because the press chamber 53 'is theninits lower position, with the valve I09 held open.

end of a snowing operaby proper manipulation of the valve handle 31.

The actuator I02 is moved to up position until the upper end of thepress chamber 53 has lapped the boss I2 on the lower face of the closurell slightly, at which time the controller I02 is moved to neutral"position. Then the controller I04 ismoved to up position, causing thepress plunger 51 to move up. At this time, the dissipation of pressurein the connection 68 in control line I28 sets the pump II8 for maximumdelivery pressure. Thus, the plunger 51 bon dioxide snow in said presschamber against said closure.

2. In a machine for making carbon dioxide snow blocks, a snow chamberhaving an open end;

means for forming carbon dioxide snow in said chamber; a plunger movablein said chamber to eject snow from said open end; a press cham- .bermovable toward and away from said snow prising a support having a firstopen-ended compresses the snow in the press chamber 53,

as indicated in Fig. 11. While the controller I04 remains in upposition, the operator shifts the controller I02 to up" position, withthe result that the press chamber 53, as well as the press plunger 51,move upwardly, finally compacting the upper end of the block, asindicated in Fig. 12, which shows the final position of and the presschamber. v

Upon the completion of the pressing operation, both controllers I02 andI04 are moved to down position. The effect is to move the plunger 51downward positively and to permit the press chamber 53 to descend bygravity as shown in Fig. 13. The controller I02 is then moved toneutral" position, to prevent the press chamber 53 from rising, and thecontroller I04 is moved to up pcsition to force the press head 51 upwarduntil the cake of snow is' lifted clear of the press chamber but notinto contact 'with the closure 1| as shown in Fig. 14. When thisposition has been reached, the controller I04 is also moved to neutral"position. The cake of snow is then removed, after which the controllerI04 is shifted to "down position, restoring the parts to the position ofFig. 9, ready for the next transfer and pressing cycle.

By snowing and pressing concurrently, 'it is possible to extend thesnowing period andto avoid the freezing effects characteristic of toorapid asnowing operation.

Since one end ofthe block is compacted by,

the plunger 51 during the first part of the pressing operation and theother end of the block is compacted by boss I2 during the finalconcurrent movement of chamber 55 and plunger 51, all of the corners ofthe block are firm and dense. The use of plunger H to eject snowpositively from the snow chamber insures quick and complete clearing ofthis chamber.

This applicationis a continuation-in-part of my application Serial No.165,196, filed Septem ber 22, 1937.

What is claimed is:

1. Apparatus for making carbon dioxide snow blocks, comprising a snowchamber and a press chamber, each having a closed end'and an open. end,said chambers being disposed in end-to- 'enjd relation with their openends adjacent each other; a single pivoted closure for sealing the openends of both chambers simultaneously; means for injecting liquid carbondioxide into said snow chamber to form snow therein; positive mechanicalmeans in said snow chamber for ejecting the plunger chamber and havingan open end in alignment with the open end of the snow chamber toreceive snow from said snow chamber; means in said press chamber forpressing snow therein; a closure common to the open ends of bothchambers; and guiding means for said closure,

remote from said chambers and serving to guide the closure betweenaninactive position and a position in which it seals against the open endof the snow chamber and open end -of said press chamber.

3. Carbon dioxide snow block apparatus, comchamber fixedly mountedthereon; means for forming carbon dioxide snow in said first chamher; asecond chamber movably mounted on said base and having an open endfacing and axially aligned with the open end of the first chamber;positively acting means for transferring snow from the first chamberinto the second chamber; means'for sealing the open ends of saidchambers, said means being thermally isolated from said chambers exceptwhen in sealing relation to the same; and means for pressing the snow insaid second chamber. 7

4. Carbon dioxide snow block apparatus, comprising a support having afirst open-ended chamber fixedly mounted thereon; means for formingcarbon dioxide snow in said first chamber; a second chamber movablymounted on said base and having an open end in alignment with the openend of the first chamber; an-ejector plunger for transferring snow fromthe first chamber into the second chamber; a single closure shiftableinto and out of.alignment with said chambers; means operable to presssaid closure into sealing engagement with the open end of the snowchamber; ,means for moving the press chamber into engagement with saidclosure; and means for pressing the snow in said second chamber againstsaid sealing means whfle said sealing means is effective to supportloose snow being formed in the first chamber.

5. Apparatus for making carbon dioxide snow blocks, comprising a'snowchamber and a press chamber, each having an open end, said chambersbeing disposed in end-to-end relation with their open ends in axialalignment; a single pivoted closure for sealing the open ends of bothchambers simultaneously; means for injecting snow therefrom; and meansfor pressing the carliquid carbon dioxide into said snow chamber to formsnow therein; a piston in the press chamber for pressing the carbondioxide snow against one side of said closure while snow is being formedin said snow chamber on theother side of the closure; and means movablewith the piston in the press chamber and located outside of the chamberfor indicating the position ofsaid piston in-said chamber.v

6. Carbon dioxide snow block apparatus, comprising a support having anopen-ended chamber movably mounted thereon; a piston in said chamber;means for moving said chamber; means for moving said piston in saidchamber; a fixed chamber-mounted on said support and having an open endfacing the open end of the movable chamber; carbon dioxide snow formingis then; opposed to the means connected to the interior of said fixedchamber; a snow ejecting plunger in said fixed chamber for transferringsnow to the movable chamber; a manually operable sealing plate forclosing the open end 01' the fixed chamber; means for locking said platein sealing relation to said chamber; and means carried by said plate forcompacting the snow in the movable chamber as the movable chamber isbrought into contact,

with the plate in its locked position.

7. Apparatus for making carbon dioxide snow blocks, comprising a fixedsnow chamber having an open end; means for injecting liquid carbondioxide into said chamber to form snow therein; a press chambercontaining a pressing means and having an open end in axial alignmentwith the open end of the fixed chamber and movable toward and from it;pressing means in said press chamber; means for transferring snow fromsaid snow chamber to said press chamber; closure means adapted to sealthe open ends or both of said chambers concurrently; and a projection onsaid closure adapted to extend into said press chamber and compact thetop of the block being formed as the press chamber is moved against saidclosure and during the pressing excursion of said pressing means,whereby both ends of the formed block are made firm and compact.

8. Carbon dioxide snow block apparatus comprising, a stationary snowchamber open at one end; intake and oil'take connections to said snowchamber for liquid and gaseous carbon dioxide respectively; a presschamber having an open end; a compressing plunger in said press chamber;means for moving the press chamber along the axis of the snow chamber;and a shiitable plate movable into and out of direct contact with theopen end of said now chamber to serve as a closure for the snow chamberwhen the press chamber is retracted, said plate including a projectionadapted to coact with the open end of the press chamber and to form asnow confining, seal therewith when the press chamber is moved towardsaid closure.

9. Carbon dioxide snow block apparatus comprising, astationary snowchamber having an open end; intake and ofitake connections to saidchamber; a pivoted plate movable into and out or direct contact with theopen end of said chamber to seal or open the same; a movable presschamber open atone end and in axial alignment with said snow chamber; apressing plunger in said press chamber; means for moving said presschamber into direct contact with said plate when the plate is in contactwith the snow chamber; and mechanical means for ejecting snow from thesnow chamber into the open end 01' the press chamber when said plate isout of alignment with the open ends of said chambers.

10. Apparatus for making carbon dioxide snow blocks, comprising a snowchamber and a press chamber, each having an open end, said chambersbeing disposed in end-to-end relation with their open ends opposed, atleast the press chamber .being movable toward and from the otherchamber; closure means for closing the open ends of said chambers, saidmeans being movable to and from a position between the chambers andincluding a boss adapted to enter the open end of the press chamber andserve as a compressing abutment therein; means for injecting liquidcarbon dioxide into said snow chamber to form snow therein; means fortransferring said snow to the press chamber when said closure iswithdrawn; a pressing plungermovable in said press boss and plunger, andsharp corners on the block are secured.

11. Carbon dioxide snow block apparatus comprising a stationary snowchamber having an open end; intake and oil'take connections to said snow-chamber for liquid and gaseous carbon dioxide respectively; a snowejecting plunger in said snow chamber; an open ended press chamber inaxial alignment withsaid snow chamber and movable toward and away fromsaid snow chamber; a shiitable closure for said snow chamber when saidpress chamber is retracted and for both of said chambers when the twoare juxtaposed; and means eflective only in the retracted position ofthe press chamber for actuating said snow ejecting plunger.

12. Carbon dioxide snow block apparatus comprising a base having astationary snow chamber mounted thereon, said chamber having an openend; a press chamber movably mounted on said base in axial alignmentwith said snow chamber and having an open end facing the open end of thesnow chamber; means for moving said press chamber toward and away fromsaid snow chamber; a shiftable closure plate movable into and out ofsealing contact with the open end of the snow chamber and adaptedto'se-rve as a closure for the snow chamber when the press chamber isretracted, or as a closure for both or said chambers when they arejuxtaposed; and guiding means for supporting said plate in thermallyisolated relation to both 0! said chambers.

13. Carbon. dioxide snow block apparatus comprising a base having astationary snow charmber mounted thereon, said chamber having an openend; a press chamber movably mounted on said base in axial alignmentwith said snow chamber and having an open end racing the open end of thesnow chamber; means for moving said press chamber toward and away fromsaid snow chamber; and a closure plate pivotally mounted on said base inthermally isolated relation to both of said chambers and adapted toserve as a closure for the open ends of both oi said chamberssimultaneously and forming the sole separating means between the loosesnow in the snow chamber and the snow block in the press chamber.

14. Carbon dioxide snow block apparatus comprising a stationary snowchamber having an open end; intake and ofltake connections to said snowchamber for liquid and gaseous carbon dioxide respectively; a snowejecting plunger in said snow chamber; an open ended press chamber inaxial alignment with said snow chamber and movable toward and away fromsaid snow chamber; means for moving said press chamber toward said snowchamber; a shiftable closure for sealing the snow chamber alone or bothof said chambers; and means controlled by the position of the presschamber for preventing operation oi' the snow ejecting plunger when thepress chamber is removed from its fully retracted position.

15. Carbon dioxide snow block apparatus comprising a snow chamber havingan open end;

chamber axially aligned with said snow chamber; means for guiding saidpress chamber in motion toward and from the snow chamber in thedirection of said axis; a closure for said snow chamber; guiding meansor said closure remote from said snow chamber; means for limiting theapproach of said press chamber toward said snow chamber to preventengagement of the two but permitting the press chamber-to engage theclosure when the latter is in position toclose the snow chamber; meansfor actuating said ejecting plunger; and an interlock serving to inhibitactuation of said ejecting plunger except in a retracted position ofsaid press chamber.

16. The combination defined inclaim 15, in which the ejecting plunger isfluid operated, and the interlock comprises a valve shiitable bymovement of the press chamber and controlling fluid which flows as anincident to operation 01 the ejecting plunger.

1'7. Apparatus for making carbon dioxide snow blocks, comprising a snowchamber and a press chamber movable with respect to said snow chamber,each of said chambers having an open end, said chambers being disposedin end-to-end relation with their open ends in axial alignment; aclosure insertable between the open ends of both chambers for sealingthem simultaneously; means for shifting the closure out of alignmentwith said chambers into inoperative position; and means effective onlywhen said press chamber is in a predetermined position for ejecting snowfrom said snow chamber.

18. Carbon dioxide snow block apparatus comprising, a stationary snowchamber having an open end; intake and ofitake connections to saidchamber; a pivoted closure movable into and out of direct contact withthe open end of said chamber to seal or open the same; a movable presschamber open at one end and in axial alignment with said snow chamber; apressing plunger in said press chamber; means for moving said presschamber into direct contact with said closure when the closure chamber;and means for actuating said plunger to elect snow from the snow chamberinto the open end of the press chamber when said 010-, sure is out ofalignment with the open ends of said chambers.-

WILLIAM E. ZIEBER.

is in contact with the snow

